1. Field of the Invention
The present invention pertains to a pressure plate assembly for a friction clutch comprising a housing arrangement; a pressure plate held in the housing arrangement with freedom to move axially; a stored-energy element; a wear-compensating device acting in the path of force transmission between the stored-energy element and the pressure plate and/or between the stored-energy element and the housing arrangement, where the wear-compensating device has at least one adjusting element able to move in an adjusting direction to compensate for wear; a clearance-producing device, comprising a gripping element, where the minimum of one gripping element has a body section, one end of which is fastened to the assembly consisting of the pressure plate and the housing, between which assembly and the stored-energy element the wear-compensating device acts, whereas the other end is designed with a blocking section projecting laterally from the body section to act on the wear-compensating device and to interact with a blocking element, which shifts its position with respect to at least one part of the gripping element when wear occurs.
2. Description of the Related Art
A pressure plate assembly of this type is known from U.S. Pat. No. 6,123,180 and is illustrated there in, for example, FIGS. 9 and 10. In this known pressure plate assembly, the wear-compensating device comprises an adjusting ring, and the body section of the gripping element extends approximately in the circumferential direction on the radially inward side of this adjusting ring. The blocking section or gripping section of the gripping element, which projects laterally from the body section, extends radially from the inside toward the wear-compensating device and projects over it radially toward the outside. In this section, i.e., the section extending radially outward beyond the wear-compensating device, the gripping element comes to rest against the blocking element, which is fastened to, for example, the housing arrangement, when wear occurs. When the gripping element, the body section of which is attached to the pressure plate, then moves together with the pressure plate upon the occurrence of wear, the radially outer end of the gripping section, i.e., the blocking section, is held up on the blocking element, and the clearance required for the following wear compensation is created between the gripping section or blocking section and the wear-compensating device.
It is the object of the present invention to improve the pressure plate assembly of the general type in question in such a way that the wear which has occurred and been detected within the pressure plate is compensated with increased precision.
According to the invention, in the area of its body section that the minimum of one gripping element interacts or can be brought into interaction with the blocking element.
In a departure from the design principle known according to state of the art, according to which the gripping element works together with the blocking element by way of a gripping or blocking section which projects laterally from the body section of the gripping element, the present invention now takes the approach that the blocking element and the gripping element interact with each other by way of the body section of the gripping element itself. It follows from this that the deformation necessarily induced in the area of the gripping element upon the occurrence of wear consists almost exclusively of a bending deformation of the body section and that torsional deformations are almost completely avoided. The consequence of avoiding the torsional deformation of the gripping element is that the extent to which the blocking section is lifted from the wear-compensating device is essentially exactly the same as the extent to which, for example, the pressure plate also moves as a result of wear, a movement which the area of the gripping element cooperating with the blocking element cannot make. In the case of the gripping element known from U.S. Pat. No. 6,123,180, however, the blocking element attacks the gripping element from the side, relative to the body section, upon the occurrence of wear, which means that the gripping element twists, with the result in turn that the gripping element, specifically the area of the gripping element which cooperates with the wear-compensating device, is not completely prevented from moving further along with the pressure plate. Instead, the twisting and the associated tilting allow the gripping or blocking section of the gripping element to move slightly toward the wear-compensating device, so that ultimately the true extent of the wear which has occurred or which has been detected is not correctly represented. Because, in the present invention, the true value is not distorted in this way, the wear which has occurred and which has been detected in the area of a friction clutch equipped with this type of pressure plate assembly can be compensated with precision.
For example, in the pressure plate assembly according to the invention, it is possible for the body section of the minimum of one gripping element to extend essentially in the circumferential direction with respect to the rotational axis, for the blocking section which acts on the minimum of one adjusting element to project radially toward the inside from the body section, and for the blocking element to project radially inward from the outside toward the body section and to overlap it radially to a certain extent. Especially the positioning of the minimum of one gripping element radially outside the minimum of one adjusting element prevents any interfering interaction between the gripping element and the stored-energy element.
To ensure with even greater certainty that, upon the occurrence of wear and thus of the interaction thus induced between the blocking element and the minimum of one gripping element, an undesirable twisting of the gripping element cannot occur, it is proposed that the blocking element overlap the body section at least up as far as the area of a longitudinal center line extending along the body section.
It is also preferable in the pressure plate assembly according to the invention for the minimum of one adjusting element to comprise an adjusting ring, which can move in the circumferential direction to accomplish the adjustment, for the body section to extend in the circumferential direction along or near the radially outer side of the adjusting ring, and for the blocking element to extend radially from the outside toward the adjusting ring.
The present invention also pertains to a friction clutch in which a pressure plate assembly according to the invention is provided.